Fuel injector arrangements are known in the prior art which have a fuel injector for distributing combustion gas, and which use a control fluid such as control oil for controlling particular combustion gas nozzle valve elements of the fuel injector, i.e., one or more combustion gas nozzle valve elements. To prevent combustion gas from unintentionally passing into the control fluid control circuit during combustion gas operation, in particular due to creepage paths along particular combustion gas nozzle valve element guides, the use of barrier fluid (barrier oil) may be provided for media separation or sealing at particular combustion gas nozzle valve element guides, i.e., within the scope of barrier fluid seals around particular combustion gas nozzle valve elements (in addition, further barrier fluid seals may be provided elsewhere in the fuel injector).
In such combustion gas injectors, in terms of operational and functional reliability it is important to reliably avoid gas leaks, for which purpose the media, namely control fluid, combustion gas, and barrier fluid, must be switched in a specified order. Such switching at preferably brief intervals must be regulated in a complicated manner from the injector periphery. Emergency shut-off situations, in which generally first the gas pressure is switched off while the control fluid pressure and the barrier oil pressure disadvantageously continue to prevail, are also problematic. This may inadvertently result in high spring load on springs installed in the injector, to such an extent that the combustion gas pressure is then no longer available for maintaining the pressure equilibrium.